Security

GitHub rejects your Git password over HTTPS. Switch the remote to SSH, or create a personal access token and store it, so pushes stop asking.

SSH offers every key you own and the server cuts you off after six. Pin one key with IdentitiesOnly, and learn why GitHub gives a different error.

SSH stops with "Host key verification failed." Read the warning correctly, decide whether the key really changed, and fix it without disabling checking.

OpenSSF is a cross-industry initiative improving open source software security. Understand why it exists, how it works, and its role in securing the software supply chain.

SBOM is a Software Bill of Materials listing all components in software. Understand why it exists, how it works, and its role in software supply chains.

Privacy and compliance fundamentals: protect user data, meet legal requirements, and build systems defensible in an audit.

Software security fundamentals: threats, vulnerabilities, and defenses. Build systems that protect data and users from attacks.

Learn how to manage multiple GitHub accounts on one computer using SSH keys. Includes step-by-step instructions, shell functions, and best practices for macOS.

Fix "Permission denied (publickey)" in SSH and Git: use the git user, load your key into ssh-agent, add it to GitHub, and set key file permissions.